Damaged key or more likely damaged key contact - replace the keyboard with a new one.

Thanks, but it's a laptop --- in the shop for a key change?

http://www.parts-people.com/index.php?action=item&id=112

Inspirion 8600

It is easy to replace - all you need is the correct Philips screwdriver:

http://docs.us.dell.com/support/edocs/systems/ins8500/en/8600cr/sm/keyboard.htm#1111863

Usually, the contact wears out, not the key - you will need to replace the entire keyboard.  What model system is it?

Thanks for the URL.  The price is reasonable.  Is it something that I can repair myself or do you have to be a member of the Geek Squad?

Thanks.  It looks easy enough.  Will try.